New cytotoxic diarylheptanoids from the rhizomes of Alpinia officinarum.

Bioassay-guided fractionation of the cytotoxic MeOH extract from the rhizomes of Alpinia officinarum Hance led to the isolation of two new diarylheptanoids named alpinoid D (1) and E (2), together with fifteen known diarylheptanoids (3 - 17). The structures of compounds 1 and 2 were elucidated on the basis of spectroscopic data and chemical evidence. The cytotoxic activity of the isolated diarylheptanoids was evaluated against the IMR-32 human neuroblastoma cell line. Among the tested compounds, 11, 12 and 14 exhibited the most potent activities with IC (50) values of 0.83, 0.23 and 0.11 microM, respectively.